With the progress of digitalization of electronic devices for commercial and industrial uses, digital filter circuits are used in various fields. A digital filter circuit can easily achieve performance characteristics which it is difficult for an analog filter circuit to achieve.
The digital filter circuit needs a control circuit to perform digital filtering processing for a desired time period after receiving an input signal. Accordingly, there is a problem that the circuit is large in scale. Moreover, there is another problem that the power consumption is large since the digital filter circuit uses many counters and flip-flops.